The human eye is a keen optical observer. It has the ability to distinguish very fine detail and subtle changes in tonal value. In imaging, fine modulation is the goal, as life-like images have greater impact. Most photo-mechanical and digital reproduction processes seek to maximize this ability. Silver-gelatin emulsions were highly successful in this regard, being capable of producing images of greater sharpness and gradation than the eye can see at normal viewing distances.
The loss of most silver-gelatin processes for the more convenient ink jet process has made this quality shortfall visible. Ink jet printers are inherently incapable of producing continuous-tone images. Instead, they must be simulated through a system of dithering, that is, simulating intermediate tonal values through the spacing of full-tone dots. This is an inherent trade-off of sharpness for gradation because a sufficient area is required for the ink jet dots to provide an adequate range of intermediate tonal values. These intermediate values often lack subtlety and can display visible banding at tonal transitions.
Ink jet printers are of a closed, proprietary nature, making any modification to overcome their inherent limitations difficult. The process by which they simulate continuous tones as well as the inks are complex and not always fully disclosed. What is needed is a process that can take the widely available ink jet printer and modify it to increase its sharpness and gradation.
Photo-mechanical, xerographic and all other non-continuous tone printing processes analogously suffer from tonal and sharpness fidelity problems. When the primary means of modulation is the size, shape or spacing of the ink dots, the inability to print at sufficiently high resolution diminishes the ability to finely modulate tone and delineate precise detail. What is also needed is a process that can take the widely available photo-mechanical, xerographic or any other non-continuous tone form of printing and modify it to increase its sharpness and gradation.